1. Field of the Invention
This invention relates to a process for the preparation of substituted triazines and derivatives thereof.
2. Background of the Related Art
Substituted triazines are commercially important compounds which find many uses in the chemical industry both as end products and intermediates. For example, 2,4,6-tris-[aminoanilino]-triazine is useful for synthesizing textile, leather and paper dyes as well as pigments. U.S. Pat. No. 4,650,867 discloses a method for preparing 2,4,6-tris-(aminophenylamino)-triazine by condensing s-chlorotriazine with a partially protected phenylenediamine and subsequently removing the protective groups.
Other substituted triazine have been found to be useful as antiozonants. It is well known that ozone causes surface cracking of conventional highly unsaturated rubber vulcanizates when the rubber is placed under strain in an ozone environment. The most severe deterioration occurs when a small number of cracks are formed which grow rapidly into deep, disruptive fissures. These ozone cracks seriously shorten the serviceable life of the article.
Chemical antiozonants have been developed which retard the formation of the ozone cracks occurring under static and dynamic conditions. Examples of antiozonants in common use include: N-phenyl-N'-(1-,3-dimethyl butyl)-p-phenylenediamine; N-phenyl-N'-isopropyl-p-phenylenediamine; N-phenyl-N'-(1,4-dimethylpentyl)-p-phenylenediamine; N-phenyl-N'-(1-methylheptyl)-p-phenylenediamine; N-phenyl-N'-cyclohexyl-p-phenylenediamine; mixed diaryl-p-phenylenediamines; N,N'-diphenyl-p-phenylenediamine; N,N'-di-beta-naphthyl-p-phenylenediamine; N,N'-bis-(1,4-dimethylpentyl)-p-phenylenediamine; N,N'-bis-(1-ethyl-3-methylpentyl)-p-phenylenediamine; N,N'-bis-(1-methylheptyl)-p-phenylenediamine; N-phenyl-N'-p-toluenesulfonyl-p-phenylenediamine, and blends of these materials.
The use of these well known paraphenylenediamine materials has improved ozone protection under both static and dynamic conditions, however, even the best of the class just described have a very strong tendency to both stain and discolor. The term "stain" or "staining" is herein used to describe the characteristic of a material to diffuse through a polymeric substrate and discolor the adjacent surface. This diffusion staining is highly objectionable in most light colored rubber articles. In tires, which is the largest application in which the ozone protection is required, the tendency to diffusion staining of the aforementioned paraphenylenediamine materials is objectionable particularly in white sidewall type tires. Even in non-white sidewall type tires, the tendency of the materials to diffuse to the surface of the tire sidewall can be objectionable in that a brown, dull surface is created on the tire sidewall. This is aesthetically objectionable in that it detracts from the general jet black, smooth appearance of a new tire. It is obvious that in a white sidewall tire, the migration of the brown discoloring material to the surface of the white sidewall is highly objectionable and generally difficult to remove during cleaning of the tire surface.
Waxes have been long utilized to inhibit ozone cracking in articles under stress in static condition by incorporating the wax into the rubber compound prior to vulcanization. The wax functions by migrating to the surface of the rubber article to form a film which acts as a physical barrier to the ozone attack. However, during dynamic flexing in service, the wax film is cracked or disrupted and the tendency is for the article to exhibit fewer and more severe ozone cracks than if no wax had been incorporated. Therefore, for many service conditions, the use of wax is impractical due to the dynamic conditions under which the article is expected to perform.
U.S. Pat. Nos. 5,120,844, 5,047,530, 4,972,010 and 4,794,135 disclose substituted 1,3,5-triazine compounds having at least one N-alkyl-p-phenylenediamino group on the triazine ring, which are useful as non-staining, long term antiozonants for unsaturated polymers. These compounds can be prepared by reacting N-alkyl phenylenediamine with a cyanuric halide. However, what is needed is a more economical and effective method of preparation.